2 * SMP support for PowerNV machines.
4 * Copyright 2011 IBM Corp.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/sched.h>
15 #include <linux/sched/hotplug.h>
16 #include <linux/smp.h>
17 #include <linux/interrupt.h>
18 #include <linux/delay.h>
19 #include <linux/init.h>
20 #include <linux/spinlock.h>
21 #include <linux/cpu.h>
26 #include <asm/machdep.h>
27 #include <asm/cputable.h>
28 #include <asm/firmware.h>
29 #include <asm/vdso_datapage.h>
30 #include <asm/cputhreads.h>
33 #include <asm/runlatch.h>
34 #include <asm/code-patching.h>
35 #include <asm/dbell.h>
36 #include <asm/kvm_ppc.h>
37 #include <asm/ppc-opcode.h>
43 #define DBG(fmt...) udbg_printf(fmt)
48 static void pnv_smp_setup_cpu(int cpu)
50 if (cpu != boot_cpuid)
53 #ifdef CONFIG_PPC_DOORBELL
54 if (cpu_has_feature(CPU_FTR_DBELL))
55 doorbell_setup_this_cpu();
59 static int pnv_smp_kick_cpu(int nr)
61 unsigned int pcpu = get_hard_smp_processor_id(nr);
62 unsigned long start_here =
63 __pa(ppc_function_entry(generic_secondary_smp_init));
67 BUG_ON(nr < 0 || nr >= NR_CPUS);
70 * If we already started or OPAL is not supported, we just
71 * kick the CPU via the PACA
73 if (paca[nr].cpu_start || !firmware_has_feature(FW_FEATURE_OPAL))
77 * At this point, the CPU can either be spinning on the way in
78 * from kexec or be inside OPAL waiting to be started for the
79 * first time. OPAL v3 allows us to query OPAL to know if it
80 * has the CPUs, so we do that
82 rc = opal_query_cpu_status(pcpu, &status);
83 if (rc != OPAL_SUCCESS) {
84 pr_warn("OPAL Error %ld querying CPU %d state\n", rc, nr);
89 * Already started, just kick it, probably coming from
92 if (status == OPAL_THREAD_STARTED)
96 * Available/inactive, let's kick it
98 if (status == OPAL_THREAD_INACTIVE) {
99 pr_devel("OPAL: Starting CPU %d (HW 0x%x)...\n", nr, pcpu);
100 rc = opal_start_cpu(pcpu, start_here);
101 if (rc != OPAL_SUCCESS) {
102 pr_warn("OPAL Error %ld starting CPU %d\n", rc, nr);
107 * An unavailable CPU (or any other unknown status)
108 * shouldn't be started. It should also
109 * not be in the possible map but currently it can
112 pr_devel("OPAL: CPU %d (HW 0x%x) is unavailable"
113 " (status %d)...\n", nr, pcpu, status);
118 return smp_generic_kick_cpu(nr);
121 #ifdef CONFIG_HOTPLUG_CPU
123 static int pnv_smp_cpu_disable(void)
125 int cpu = smp_processor_id();
127 /* This is identical to pSeries... might consolidate by
128 * moving migrate_irqs_away to a ppc_md with default to
129 * the generic fixup_irqs. --BenH.
131 set_cpu_online(cpu, false);
132 vdso_data->processorCount--;
133 if (cpu == boot_cpuid)
134 boot_cpuid = cpumask_any(cpu_online_mask);
135 xics_migrate_irqs_away();
139 static void pnv_smp_cpu_kill_self(void)
142 unsigned long srr1, wmask;
145 /* Standard hot unplug procedure */
148 current->active_mm = NULL; /* for sanity */
149 cpu = smp_processor_id();
150 DBG("CPU%d offline\n", cpu);
151 generic_set_cpu_dead(cpu);
154 wmask = SRR1_WAKEMASK;
155 if (cpu_has_feature(CPU_FTR_ARCH_207S))
156 wmask = SRR1_WAKEMASK_P8;
158 idle_states = pnv_get_supported_cpuidle_states();
160 /* We don't want to take decrementer interrupts while we are offline,
161 * so clear LPCR:PECE1. We keep PECE2 (and LPCR_PECE_HVEE on P9)
162 * enabled as to let IPIs in.
164 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1);
167 * Hard-disable interrupts, and then clear irq_happened flags
168 * that we can safely ignore while off-line, since they
169 * are for things for which we do no processing when off-line
170 * (or in the case of HMI, all the processing we need to do
171 * is done in lower-level real-mode code).
174 local_paca->irq_happened &= ~(PACA_IRQ_DEC | PACA_IRQ_HMI);
176 while (!generic_check_cpu_restart(cpu)) {
178 * Clear IPI flag, since we don't handle IPIs while
179 * offline, except for those when changing micro-threading
180 * mode, which are handled explicitly below, and those
181 * for coming online, which are handled via
182 * generic_check_cpu_restart() calls.
184 kvmppc_set_host_ipi(cpu, 0);
186 ppc64_runlatch_off();
188 if (cpu_has_feature(CPU_FTR_ARCH_300)) {
189 srr1 = power9_idle_stop(pnv_deepest_stop_psscr_val,
190 pnv_deepest_stop_psscr_mask);
191 } else if (idle_states & OPAL_PM_WINKLE_ENABLED) {
192 srr1 = power7_winkle();
193 } else if ((idle_states & OPAL_PM_SLEEP_ENABLED) ||
194 (idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) {
195 srr1 = power7_sleep();
197 srr1 = power7_nap(1);
203 * If the SRR1 value indicates that we woke up due to
204 * an external interrupt, then clear the interrupt.
205 * We clear the interrupt before checking for the
206 * reason, so as to avoid a race where we wake up for
207 * some other reason, find nothing and clear the interrupt
208 * just as some other cpu is sending us an interrupt.
209 * If we returned from power7_nap as a result of
210 * having finished executing in a KVM guest, then srr1
213 if (((srr1 & wmask) == SRR1_WAKEEE) ||
214 ((srr1 & wmask) == SRR1_WAKEHVI) ||
215 (local_paca->irq_happened & PACA_IRQ_EE)) {
216 if (cpu_has_feature(CPU_FTR_ARCH_300))
217 icp_opal_flush_interrupt();
219 icp_native_flush_interrupt();
220 } else if ((srr1 & wmask) == SRR1_WAKEHDBELL) {
221 unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
222 asm volatile(PPC_MSGCLR(%0) : : "r" (msg));
224 local_paca->irq_happened &= ~(PACA_IRQ_EE | PACA_IRQ_DBELL);
227 if (cpu_core_split_required())
230 if (srr1 && !generic_check_cpu_restart(cpu))
231 DBG("CPU%d Unexpected exit while offline !\n", cpu);
234 /* Re-enable decrementer interrupts */
235 mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_PECE1);
236 DBG("CPU%d coming online...\n", cpu);
239 #endif /* CONFIG_HOTPLUG_CPU */
241 static int pnv_cpu_bootable(unsigned int nr)
244 * Starting with POWER8, the subcore logic relies on all threads of a
245 * core being booted so that they can participate in split mode
246 * switches. So on those machines we ignore the smt_enabled_at_boot
247 * setting (smt-enabled on the kernel command line).
249 if (cpu_has_feature(CPU_FTR_ARCH_207S))
252 return smp_generic_cpu_bootable(nr);
255 static struct smp_ops_t pnv_smp_ops = {
256 .message_pass = smp_muxed_ipi_message_pass,
257 .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */
258 .probe = xics_smp_probe,
259 .kick_cpu = pnv_smp_kick_cpu,
260 .setup_cpu = pnv_smp_setup_cpu,
261 .cpu_bootable = pnv_cpu_bootable,
262 #ifdef CONFIG_HOTPLUG_CPU
263 .cpu_disable = pnv_smp_cpu_disable,
264 .cpu_die = generic_cpu_die,
265 #endif /* CONFIG_HOTPLUG_CPU */
268 /* This is called very early during platform setup_arch */
269 void __init pnv_smp_init(void)
271 smp_ops = &pnv_smp_ops;
273 #ifdef CONFIG_HOTPLUG_CPU
274 ppc_md.cpu_die = pnv_smp_cpu_kill_self;